With support from the Chemical Measurement and Imaging Program in the Division of Chemistry and co-fund from the Molecular Biophysics program in the Division of Molecular and Cellular Biosciences, Professor Brandon Ruotolo and his group at the University of Michigan will develop a nano-electrospray ionization (nESI) combined with ion mobility-mass spectrometry (IM-MS) technique as a key analytical tool for ascertaining the global structural consequences of drug molecule binding within multiprotein complexes. This unconventional approach will start by removing the water surrounding native-state multiprotein/drug complexes, it will then imbue these desolvated proteins with ionic charge, and then subsequently sort these protein complex ions according to both their size/shape and their mass in the gas phase. Developing nESI-IM-MS so that detailed information on drug/protein interactions can be obtained requires 1) a deeper physical understanding of how desolvated proteins can change their shape and structure (e.g. through protein unfolding) when given excess thermal energy in a vacuum and 2) the invention of robust protocols that use such internal temperature-induced protein/drug complex unfolding as a means of rapidly screening for new multiprotein inhibitors.
The intellectual merits of the proposed research primarily include the development of the new analytical tools described above, combined with a deeper chemical-physics type description of the protein unfolding processes operative in the absence of bulk solvent. Given the general importance of multiprotein complexes we expect that our work will be generally impactful, but we expect especially high impact within both the IM-MS and protein structure communities. The broader impacts of the proposed research include (a) the highly interdisciplinary training of participating graduate and undergraduate students in state-of-the-art IM-MS instrumentation, protein purification, protein-ligand screening, unimolecular reaction dynamics, gas-phase kinetics, and protein folding/structure. (b) The inclusion of students from historically underrepresented groups, in part through an NSF-funded REU program. (c) Developing an enhanced mass spectrometry curriculum at the University of Michigan, including novel laboratory exercises and instrumentation designed for undergraduate education, as well as a modular lecture course designed for graduate students. (d) Outreach to high school students through the Michigan Math and Science Scholars program at the University of Michigan.
